Control circuit and method for stud welding gun lifting solenoid

摘要

A solenoid power control circuit provides full power during lifting and reduced power during maintaining a lift condition in a lifting solenoid of an electric arc stud welding gun. During the stud lifting portion of a stud welding process, relatively high power is provided to the lifting solenoid to effect work necessary to accomplish the lift; but after a lifted condition has been achieved, the invention phases back power to reduce the energy dissipated while the stud and the lifting solenoid are maintained in lifted condition. A relaxation oscillator having two different charging time constants that can be selected to provide long or short phase delay is employed for the phase modulation control of lifting solenoid energization.